str1 = "hello world"
str2 = 'hello world'
str3 = '''hello
world'''
print(str1)
print(str2)
print(str3)
print('hello \'world') #\ 转义符
print('123-----{0}----{1}-----{2}'.format(4,5,6))
str1 = 'hello'
print(f'123------{str1}')

# 显示进度
for i in range(0, 101, 2):
    print("=============开始下载=============")
    if i == 100:
        print("下载完成")
    else:
        #print(f'{i}%', '[', "*"*(i//2), "."*((100-i)//2), ']')
        str4 = "*"*(i//2) + "."*((100-i)//2)
        print(f'{i}%[{str4}]')

